Treatment of congestive heart failure

ABSTRACT

Combinations of diuretics and vasopressin antagonists are useful to slow and reverse the symptoms and process of congestive heart failure, to increase the excretion of water in the urine, and to decrease the excretion of sodium and potassium ions in urine. Preferred vasopressin antagonists have the formula (I) wherein R and R 5  are hydrogen or lower alkyl; R 1 , R 2 , and R 3  are hydrogen, halo, alkyl, alkoxy, and amino; and R 4  is hydrogen or phenyl, and a pharmaceutically acceptable salt thereof

FIELD OF THE INVENTION

[0001] This invention relates to combinations of vasopressin antagonistsand diuretic agents for use in treating edematous conditions such ascongestive heart failure.

BACKGROUND OF THE INVENTION

[0002] Congestive heart failure (CHF) is a pathophysiological state inwhich the heart is unable to pump sufficient blood to meet the metabolicneeds of the body. The underlying basis of this disorder is a deficiencyof mvocardial contractility, resulting in a decreased mechanical abilityto pump blood and in turn, a decreased cardiac output. Congestive heartfailure may result from a number of factors affecting the myocardium,altering systolic and/or diastolic function. As the conditionprogresses, activation of both the sympathetic nervous system and therenin-angiotensin-aldosterone system lead to an increase in the totalperipheral resistance. In addition, elevated levels of argininevasopressin (AVP) have been reported in some patients with heartfailure, although its pathophysiologic role is unknown. It has beenpostulated that the increase in AVP may provide increased systemicvascular resistance and impaired water excretion as a compensatorymechanism to the low cardiac output associated with CHF.

[0003] Arginine vasopressin, also known as antidiuretic hormone (ADH),is synthesized in the magnocellular neurosecretory cells of theparaventricular and supraoptic nuclei of the hypothalamus and stored inthe posterior pituitary. There are 2 classes of AVP receptors. V₁ andV₂. There are 2 subclasses of V₁ receptors, V_(1A) and V_(1B). V_(1A)receptors are found in the vasculature, and mediate the pressor responseof AVP by increasing the contraction of blood vessels. V_(1A) receptorsare also found on platelets, where they mediate platelet aggregation.V_(1B) receptors are located in the anterior pituitary, and mediateadrenocorticotropic hormone (ACTH ) release. V₂ receptors are located inthe collecting ducts of the kidney: they are coupled to aquaporinechannels and modulate free water clearance. Arginine vasopressin isreleased into the circulation in response to an increase in plasmaosmolality (mediated by osmoreceptors) or a decrease in plasma volume orblood pressure (mediated by baroceptors). However, there are otherstimuli for AVP release, including norepinephrine, angiotensin II,emotion, nausea and vomiting, and fever.

[0004] Heart failure is characterized by increased sympathetic nervoussystem activity and changes in several neurohormonal factors, such asangiotensin II, aldosterone. endothelin-1, and atrial natriureticfactor. In patients with advanced CHF, plasma levels of AVP are alsoincreased. While the mechanism of AVP release in CHF is notwell-understood, infusion of AVP into CHF patients results in anincrease in systemic vascular resistance and a redistribution of cardiacoutput. These observations suggest that the increased levels of AVPobserved in patients with severe CHF play a role in the pathogenesis ofthis disease. Several compounds are known which antagonize the hormonaleffects of AVP, for example the benzazepines disclosed in U.S. Pat. No.5,723,606.

[0005] The cardiac dysfunction underlying CHF results in a decreasedeffective tissue perfusion, which in turn stimulates therenin-angiotensin-aldosterone and sympathetic nervous systems to promoteNa⁺ retention by the kidney, which can result in the formation of edema.Patients with CHF and evidence of pulmonary congestion or peripheraledema are routinely treated with diuretics. Thiazide diuretics, whichact on the distal convoluted tubule of the kidney by inhibiting theNa⁺—Cl⁻ cotransporter, may initially be employed. However. they produceonly a slight increase (5%-8%) in the amount of sodium excretion by thekidney, and subject the patient to risk of hypokalemia (low bloodpotassium) and hyponatremia. In patients with more advanced heartfailure and signs of extracellular fluid accumulation, loop diureticsare generally used. Loop diuretics, such as furosemide, act at the thickascending limb of the loop of Henle by competing for the Cl³¹ site onthe Na⁺—K⁺—Cl⁻ transporter. These diuretics are capable of increasingthe fractional sodium excretion to more than 20% of the filtered load,albeit at an even greater risk of potassium wasting in the urine andhypokalemia and hyponatremia in the serum.

[0006] We have now discovered that the use of diuretics in combinationwith compounds which inhibit vasopressin enzymes is surprisinglyeffective in promoting increased clearance of fluid by the kidney, anddecreased excretion of sodium and potassium in the urine, therebyminimizing the risk of electrolyte disturbance such as hypokalemia andhyponatremia. An object of this invention is thus to providecompositions comprising a vasopressin antagonist in combination with aloop diuretic agent, and a method for treating edematous conditions suchas CHF using such compositions.

SUMMARY OF THE INVENTION

[0007] This invention provides a composition comprising a diuretic agentand a vasopressin antagonist. The invention also provides a method fortreating edematous conditions such as CHF, and promoting increased fluidclearance by the kidney, and maintenance of electrolyte balance in amammal by decreasing excretion of sodium and potassium in the urineotherwise caused by the diuretic agent alone.

[0008] Any diuretic agent can be used in combination with anyvasopressin antagonist according to this invention. In a preferredembodiment, the diuretic agent is a loop diuretic agent. Loop diureticsare compounds that act on the ascending limb of the loop of Henle and onthe proximal and distal tubes in the kidneys of animals. The compoundsare routinely used to treat edema associated with CHF, cirrhosis of theliver, and renal disease. Typical loop diuretics include bumetinide,ethacrynic acid, furosemide, piretanide, and torsemide. Other diureticscan also be used in this invention, including agents such aschlorothiazide, hydrochlorothiazide, triamterene, spironolactone,eplerenone, metolazone, acetazolamide, amiloride, and polythiozide. Apreferred loop diuretic is furosemide (see U.S. Pat. No. 5.256,687).

[0009] The vasopressin antagonist to be employed is any chemicalcompound that is effective in inhibiting the biological activity of anyarginine vasopressin or antidiuretic hormone. Numerous compounds areknout to be vasopressin antagonists, and any of such compounds can beutilized in the composition of this invention.

[0010] In a preferred embodiment the vasopressin antagonist to beutilized is a condensed benzazepine such as those described in U.S. Pat.No. 5.723.606, incorporated herein by reference. In a further preferredembodiment, the vasopressin antagonist is an imidazo benzazepine of theFormula I

[0011] wherein R and R⁵ are hydrogen or lower alkyl;

[0012] R¹, R², and R³ independently are hydrogen, halo, lower alkyl,lower alkoxy, amino, alkylamino, or dialkylamino; and

[0013] R⁴ is hydrogen, phenyl or substituted phenyl, andpharmaceutically acceptable salts thereof.

[0014] An especially preferred vasopressin antagonist to be used inaccordance with this invention is conivaptan, which isN-[4-(2-methyl-4,5,6-tetrahydromidazo[4,5-d][1]benzazepin-6-ylcarbonyl)phenyl]biphenyl-2-carboxamidehydrochloride. Conivaptan is also referred to as CI-1025 and YM087, andhas the structural formula below

[0015] Other vasopressin antagonists that can be employed accordingly tothis invention include the benzoheterocyclic compounds described in U.S.Pat. No. 5,258,510, incorporated herein by reference. Preferredcompounds from this class to be used herein include the following:

[0016]5-Dimethylamino-1-[4-(2-methylbenzoylamino)-benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0017]5-Dimethylamino-1-[2-chloro-4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0018]5-Methylamino-1-[2-chloro4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0019]5-Cyclopropylamino-1-[2-chloro4-(2-methylbenzoylamino)benzoxyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0020]5-Cyclopropylamino-1-[2-chloro-4-(2-chlorobenzoylamino)benzoxyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0021]5-Dimethylamino-1-[2-methyl-4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine;

[0022]5-Dimethylamino-1-[2-methoxy4-(2-methylbenzoylamino)benzoyl]-1,2,3,4-tetrahydroquinoline;

[0023]7-Chloro-5-methylamino-1-[4-(2-methylbenzoylamino)benzoxyl]-2,3,4,5-tetrahydro-1H-benzazepine;and

[0024]7-Chloro-5-methylamino-1-[4-(2-chlorobenzoylamino)benzoxyl]-2,3,4,5-tetrahydro-1H-benzazepine.

[0025] Other vasopressin antagonists that can be employed according tothis invention include those described in U.S. Pat. Nos. 5,225,402:5,258,510: 5,338,755; 5,719,155; and 5,710,150, all of which areincorporated herein by reference. Specific vasopressin antagonistsinclude YM471, OPC-331260, OPC-21268, OPC-41061, SR-121463, SR49059,VPA-985. CL-385004, FR-161282, JVT-605, VP-339, WAY-140288, and thelike.

[0026] The compositions provided by this invention will contain adiuretic agent. preferably a loop diuretic, and a vasopressin antagonistin a weight ratio of about 0.05:1 to about 1000:1, and typically about1:1 to about 500:1 and ideally about 1:1 to about 10:1. A typicalcomposition, for example, will comprise about 40 mg to about 80 mg ofthe loop diuretic furosemide together with about 5 mg to about 40 mg ofconivaptan. Such compositions w ill be administered to adult humanssuffering from edematous conditions such as CHF.

[0027] A further embodiment of this invention is a method for treatingCHF comprising administering to a patient suffering from CHF and in needof treatment an effective amount of a diuretic agent in combination withan effective amount of vasopressin antagonist.

[0028] Another embodiment is a method for decreasing the excretion ofsodium and potassium ions in the urine of an animal comprisingadministering a diuretic agent in combination with a vasopressinantagonist.

[0029] Still another embodiment of the invention is a method forincreasing the amount of fluids secreted by an animal via the kidneycomprising administering an effective amount of diuretic agent incombination with a vasopressin antagonist.

[0030] Another embodiment is a method for treating edematous states.

[0031] All that is required to practice the methods of this invention isto administer amounts of a diuretic agent and a vasopressin antagonistthat are effective to treat CHF and to reduce electrolyte imbalance inmammals. The agents can be administered individually, or they can beformulated together into a single composition.

DESCRIPTION OF FIGURES

[0032]FIG. 1 shows the change in urine osmolality (mOsm/kg) in patientsreceiving various dose combinations of furosemide and conivaptan.

[0033]FIG. 2 shows the percentage reduction in urine osmolality causedby various dose combinations of furosemide and conivaptan and thesynergy between the two agents.

[0034]FIG. 3 shows the total urine sodium concentration (mEq) followingvarious dose combinations of furosemide and conivaptan (conivaptanantagonizes the excretion of sodium).

[0035]FIG. 4 shows the total urine potassium concentration (mEq)following various dose combinations of furosemide and conivaptan.Conivaptan antagonizes the urinary excretion of potassium by furosemide.

DETAILED DESCRIPTION OF THE INVENTION

[0036] The ability of a combination of a diuretic agent together with avasopressin antagonist to reduce electrolyte imbalance and to treat CHFhas been established in a controlled clinical trial.

[0037] Preclinical pharmacologic studies have demonstrated potentbinding of YM087 conivaptan to AVP receptors and antagonism of thevascular and renal effects of AVP. YM087 has high affinity forV_(1A)-and V₂-receptors with pKi (negative log of the binding inhibitionconstant) of 8.20 for human V_(1A)-receptors and 8.95 for humanV₂-receptors expressed in COS-1 cells.

[0038] Clinical Pharmacology

[0039] YM087 given orally to rats antagonizes the AVP-induced pressorresponse (V_(1A) antagonism) in a dose-related manner, with the dosethat reduced the AVP response by 50% (ID₅₀) being 0.32 mg/kg; ID₅₀ for asimilar experiment using intravenous (IV) YM087 in dogs was 0.026 mg/kg.In conscious dogs, oral YM087 (0.03 to 0.3 mg/kg) increased urinaryoutput (V₂ antagonism) and reduced urinary osmolality (from 1500 to<100mOsm/kg H₂O) in a dose-related manner. Unlike furosemide. YM087 haslittle or no effect on urinary sodium (Na) or potassium (K) excretion.In dogs with heart failure induced by rapid right ventricular pacing,intravenous administration of YM087 (0.1 mg/kg) significantly improvedthe depressed cardiac function and produced a water diuresis.

[0040] Oral absorption of YM087 is rapid (peak concentrations reachedbetween 0.5 to 1 hour in the rat and dog, respectively) and occurspredominantly in the small intestine. There is a marked food effect withabsorption reduced by>50% in dogs after a meal. The eliminationhalf-life is 1 hour in rats and 2 hours in dogs. Mass balance studiesshow the majority of radioactive tracer excreted in the feces. Thepreclinical toxicologic potential of YM087 has been extensivelyevaluated. and all findings were evaluated for relevance to human riskassessment and impact on clinical trial design. Findings of potentialconcern were bone marrow changes in dogs and effects on fertility inrats.

[0041] Histopathologic changes in bone marrow were observed in both 2-and 13-week oral studies in dogs with systemic exposures 28- to 87-foldhigher than the maximum anticipated human exposure. Decreased peripheralerythrocyte, leukocyte, and/or platelet counts occurred in affected dogsin the 13-week study. Bone marrow and peripheral blood changes werereversible.

[0042] YM087 did not affect reproductive performance of male rats. Inthe 13-week, repeated oral dose study in rats, more females at 10 mg/kgwere in diestrus or proestrus and fewer were in estrus than in controls,and uterine weights were decreased at all doses; associated systemicexposures were 0.06- to 3.2-fold the maximum anticipated human exposure.In the female fertility study in rats, reduced fertility index,increased implantation loss, and decreased live fetuses were observed infemales given 100 mg/kg orally for 2 weeks prior to mating withuntreated males. Effects on estrous cycle and fertility in female ratsmay be related to alterations in serum hormone levels resulting frompharmacologic activity of YM087. YM087 was not teratogenic in rats orrabbits.

[0043] Other drug-related effects, including diuresis and hepatocellularhypertrophy, were of less concern due to the nature of the effects orthe high exposures at which the effects occurred compared to exposuresanticipated in clinical trials.

[0044] YM087 was not mutagenic in bacteria, and was not clastogenic inhuman lymphocytes in vitro or in bone marrow of rats. No toxicity wasobserved in 4-week, IV studies with the glycerin formulation at maximumachievable doses. 2.5 mg/kg in rats and 2 mg/kg in dogs.

[0045] In summary, toxicological findings of potential concern for humanrisk assessment were reversible effects on bone marrow in dogs andreversible effects on estrus cycle and decreased fertility in rats.Findings in bone marrow were observed at exposures in excess of 23 timesexposure expected in humans given the maximum dose of 120 mg once daily(QD), while effects on estrus cycle occurred at exposures from 0.05- to3-fold the expected human exposure at 120 mg QD. Other drug-relatedfindings in toxicology studies were considered secondary topharmacologic activity or a functional adaptation to exposure to YM087.

[0046] YM087 has been given to approximately 250 healthy patients whoparticipated in a total of 15 Phase 1 studies (8 in Japan and 7 inEurope). Subjects taking oral medication received either a single doseof YM087 (dose range 0.2 through 120 mg) QD or 30 or 120 mg YM087administered as a divided dose twice daily (BID). Subjects receivedYM087 as a single IV injection once daily over a dose range of 0.2 to250 μg/kg or up to a maximum of 50 mg.

[0047] Inhibition of AVP-induced platelet aggregation (evidence ofV_(1A) antagonist activity) was seen among subjects who received YM087at 20 mg/day orally or 2.5 mg IV. Total inhibition of AVP-induced dermalvasoconstriction was observed among subjects who received YM087 50 mgIV.

[0048] Normal subjects have demonstrated aquaretic action (evidence ofV₂-receptor antagonism) accompanied by a decrease in urine osmolaritystarting at 15 mg oral or 50 μg/kg IV. At higher doses aquaretic effectswere more pronounced and at 120 mg QD or 60 mg BID given orally or 50 mggiven IV were considered too uncomfortable in normal subjects to betolerable. YM087 at IV doses up to 250 μg/kg and 50 mg/day increasedurine production rate for up to 3 and 6 hours postdosing, respectively.

[0049] Under fasting conditions, YM087 is rapidly absorbed, time tomaximum plasma concentration (tmax) being reached at around 1 hour. Themean oral bioavailability of a 60-mg dose is 44% under fastingconditions: bioavailability is decreased after intake with food. Ahigh-fat breakfast reduced bioavailability of single 15- to 90-mg dosesof YM087 to 43% to 59% of the fasted value, and peak plasma levels werereduced to 24% to 54% of the fasting value. Oral YM087 demonstrated anonlinear pharmacokinetic profile. Repeated BID oral doses of YM087.60mg. result in unexpectedly high plasma levels after the second dose.possibly caused by reduced first-pass metabolism. YM087 displays 2compartment pharmacokinetics, with an elimination half-life of 4 to 5hours. Elderly subjects have a similar elimination half-life as healthy,young volunteers.

[0050] The pharmacokinetics of orally administered YM087 (20 mg) werenot affected when combined with either 0.5 mg IV digoxin or 25 mg oralcaptopril (each given as a single dose).

[0051] Safety

[0052] Among approximately 250 subjects treated, no major safetyconcerns were identified. One patient with severe CHF who received YM08780 mg/day for 4 days experienced a generalized tonic clonic seizure,which the investigator could not exclude as related to study drug. Themost frequent adverse events regardless of treatment association weremild or moderate thirst and mild headache. Other adverse events includedflushes, a sensation of cold extremities, abdominal complaints, abnormalstools, syncope, dizziness, palpitations, and postural hypotension.Three subjects who received YM087 and one subject who received placebodeveloped minor, reversible decreases in white blood cell counts. Nodrug-related trend was observed in biochemical or hematologicallaboratory parameters. At higher doses, urinary osmolarity decreased andplasma osmolarity increased with or without an increase in plasmasodium. These observations were considered related to antagonism of V₂receptors and not a safety concern. Vital signs (blood pressure andheart rate) were unaffected by YM087.

[0053] Study Rationale

[0054] The edematous condition resulting from CHF develops from adecreased effective tissue perfusion, which in turn stimulates therenin-angiotensin-aldosterone and sympathetic nervous systems to promoteNa⁺ retention by the kidney. which can result in the formation of edema.Patients with CHF and evidence of edema are routinely treated withdiuretics. Thiazide diuretics, which act on the distal convoluted tubuleof the kidney by inhibiting the Na⁺—Cl⁻ cotransporter. may initially beemployed. However, they produce only a slight increase (5%-8%) in theamount of sodium excretion by the kidney and expose the patient to riskof hypokalemia and other disorders associated with electrolytedisorders. In patients with more advanced heart failure and signs ofextracellular fluid accumulation, loop diuretics are generally used.Loop diuretics, such as furosemide, act at the thick ascending limb ofthe loop of Henle by competing for the Cl⁻ site on the Na⁺—K⁺—Cl⁻transporter. These diuretics are capable of increasing the fractionalsodium excretion to more than 20% of the filtered load. albeit at aneven greater risk of hypokalemia and other electrolyte disorders.

[0055] At the kidney, AVP acts via the V₂ receptors in the principalcells of the collecting duct to increase water reabsorption. The bindingof AVP to V₂ receptors results in an increase in cytosolic cAMP (via alinked G protein) which acts as a second messenger, and results in anincrease in the “trafficking” of aquaporin 2 (AQP2) water channels fromintracellular vesicles to the apical plasma membrane of the principalcells. While this shuttling of AQP2 occurs shortly following stimulationof the V₂ receptor, longer-term chances also occur in the form of anincrease in AQP2 proteins. As YM087 antagonizes the binding of AVP tothe V₂ receptor, it is reasonable to postulate that its mechanism ofaction is via the decrease in the trafficking and production of AQP2 tothe plasma membrane of the principal cells of the collecting duct.

[0056] These findings indicate that furosemide and YM087 act atdifferent segments of the nephron, and act via different mechanisms ofaction. Agents that act at different portions of the kidney can be ofimportance in patients with CHF and other edematous states who sometimesdevelop resistance to loop diuretics, especially when they have beenused chronically for some time. The addition of a hormone antagonistwhich would increase the excretion of solute-free water (and thus notincrease sodium loss) and simultaneously limit potassium losses, mightproduce an added benefit in the treatment of CHF patients who arecurrently on a loop diuretic. Therefore, this study will be conducted toassess the effect of concomitant treatment with the vasopressinantagonist. YM087, and a commonly used diuretic, furosemide, in patientswith a prototypical edematous condition, namely CHF.

[0057] Study Objectives

[0058] The objectives of this study are:

[0059] To assess the effect of concomitant treatment with YM087 andfurosemide in CHF patients;

[0060] To determine the safety of giving these two agents concomitantlyto CHF patients: and

[0061] To assess the pharmacodynamic parameters of oral YM087 when givenwith furosemide

[0062] Study Design

[0063] This is an open-label, randomized study assessing the effect onthe safety and efficacy of oral YM087 (20 or 40 mg QD) when givenconcomitantly with oral furosemide (40 or 80 mg QD) to patients withCHF.

[0064] This study is comprised of 4 phases: Screening, FurosemideBalance, Baseline, and Treatment (Scheme 1, Study Design). Patients willbe randomized to 1 of 4 treatment combinations: (a) furosemide 40 mg QDand YM087 20 mg QD; (b) furosemide 40 mg QD and YM087 40 mg QD; (c)furosemide 80 mg QD and YM087 20 mg QD; or (d) furosemide 80 mg QD andYM087 40 mg QD. Patients will be treated on an outpatient basis, andwill come for clinic visits at Screening and on Study Days 1, end of Day4 (beginning of Day 5), and each day of treatment (Days 5 through 9[beginning of Day 10]). All tests scheduled to be done at the 24-hourtime point will be done prior to the next dose of study medication.Urine collections will be done for the 24 hours prior to the visit.

[0065] Study Schedule

[0066] Screening Phase (1 Week)

[0067] The Screening Phase allows the investigator to evaluate patientswho qualify for entry into the study and to assess initial values for anumber of study parameters (ie. clinical laboratory and urinalysisvalues including serum and urine electrolytes). An informed consent willbe signed and patients will provide medical history, includingdocumentation of New York Heart Association (NYHA) Class II/III CHF. Aphysical examination will also be performed at this time.

[0068] Furosemide Balance Phase (4 Days)

[0069] This phase allows the patient to achieve sodium and fluid balanceon the background dose of furosemide. The patient will be randomized to1 of the 4 arms of the study, and during this phase, will receive thedose of furosemide (either 40 or 80 mg/day) to which he/she israndomized. The dose should be given in the morning (before breakfast).During this phase and throughout the remainder of the study, patientswill monitor their weight daily.

[0070] Baseline Phase (2 Days)

[0071] During the Baseline Phase, the patient will continue to receivethe dose of furosemide (either 40 or 80 mg/day) to which he/she has beenrandomized. Patients will be given their dose of furosemide in theclinic for each of these days. This phase will be used to establishbaseline values for a number of study parameters. Various clinicallaboratory parameters (eg, serum and urine sodium. and plasma and urineosmolalities), free water clearance, effective water clearance, andsafety profiles will be obtained. On Day 6, patients will remain in theclinic during the first 6 hours of the study, in order to collect bloodand urine samples at various time points. Patients will then be allowedto return home overnight (continuing to collect their urine for the24-hour urine sample), and will return to the clinic the followingmorning at their scheduled visit.

[0072] Treatment Phase (3 Days)

[0073] This phase is used to determine the effect of concomitanttreatment with furosemide and YM087. In addition to the background doseof furosemide (40 or 80 mg/day), patients will receive YM087 at the doseto which they have been randomized (20 or 40 mg QD) for 3 days (StudyDays 7-9). Both drugs will be administered at the same time orally oncedaily 1 hour before breakfast with 100 mL water. Furosemide and YM087will be dispensed in the clinic on these days (Study Days 7, 8, and 9).On Day 9, patients will remain in the clinic during the first 6 hours ofthe study, in order to collect blood and urine samples at various timepoints. Patients will then be allowed to return home overnight(continuing to collect their urine for the 24-hour urine sample), andwill return to the clinic the following morning for their scheduledvisit.

[0074] If at any time, the investigator judges the patient's volumestatus to be abnormally decreased, the next dose of furosemide may bedecreased by one-half. The dose of furosemide can be further decreasedby one-half at any later assessment in which the volume status is stillabnormal.

[0075] Fluid and Sodium Intake

[0076] Patients will have their sodium and fluid intake assessed priorto the Baseline Phase. CHF patients should be maintained on thesodium-restricted diet that is typically prescribed for these patients.A dietician or nurse coordinator will determine the contents of diet anddaily calorie intake, salt consumption, and volume of water consumed inthe diet. These levels will be maintained throughout the study period.Total fluid intake (not including water in food) may not exceed 2.0L/day. Fluid intake will be assessed on a daily basis.

[0077] Urine Output

[0078] A 24-hour urine specimen will be collected on Study Days 4through 9. Samples will be collected at intervals on Study Days 6 and 9,and subsequently pooled to obtain the total 24-hour sample. Urinecollection will begin following the administration of furosemide aloneor furosemide and YM087 (at approximately 7 AM).

[0079] Study Population

[0080] Source and Number of Patients

[0081] Number of Patients: 3 to 6 patients per arm; 12 to 24 patientstotal Source: Outpatients

[0082] Patient-selection Criteria

[0083] Inclusion Criteria p These criteria are mandatory and must be metto provide evaluable data.

[0084] Males or females 18 to 85 years of age

[0085] Females must be postmenopausal, surgically sterilized orpracticing a barrier method of birth control so that in the opinion ofthe investigator, they will not become pregnant during the study;

[0086] Congestive heart failure with Class II or III functionalimpairment by New York Heart Association criteria (Appendix C);

[0087] At screening, current therapy for chronic heart failureconsisting of at least 2 months duration of an ACE inhibitor. β-blocker(optional), and digoxin (optional);

[0088] Doses of digoxin, ACE inhibitors, and/or β-blockers, must havebeen held constant for 7 days prior to the Balance Phase: and

[0089] At screening, patients must have been receiving a dose offurosemide of between 40 and 160 mg/day.

[0090] Exclusion Criteria

[0091] Breast-feeding or pregnant;

[0092] Excessive peripheral edema (>2+, ie, above the knee) or lack ofperipheral edema, suggesting volume depletion;

[0093] Significant renal impairment (serum creatinine>2.5 mg/dL orcreatinine clearance<30 mL/min); or nephrotic syndrome;

[0094] Known urinary outflow obstruction (eg, stenosis, stone. tumor.etc):

[0095] Alanine aminotransferase (ALT) or aspartate aminotransferase(AST) >3×upper limit of normal (ULN) and/or bilirubin ≧2.5 mg/dL: orcirrhosis with ascites:

[0096] Active myocarditis, constrictive pericarditis, or activevasculitis due to collagen vascular disease;

[0097] Uncontrolled hyper- or hypothyroidism;

[0098] Adrenal insufficiency (AM cortisol<7 μg/dL);

[0099] Serious hematological diseases (eg, severe anemia, Hgb<10 g/dL;leukopenia, WBC<4000/μL);

[0100] Significant hypotension (SBP<95) or uncontrolled hypertension:

[0101] Concurrent enrollment in a chemotherapy or radiation regimen;

[0102] Unstable angina or acute myocardial infarction within 30 days ofthe screening visit;

[0103] Treatment with inotropic drugs (eg, dobutamine, dopamine,milrinone, amrinone, etc) within 30 days of the screening visit;

[0104] Participation in another clinical trial of an investigationaldrug (including placebo) within the 30 days prior to screening for entryinto the present study;

[0105] History of current or past use of illicit drugs or alcoholismunless abstinence can be documented for ≧6 months:

[0106] Other medical conditions, such as significant obstructive cardiacvalvular disease and/or hypertrophic subaortic stenosis, obstructivelung disease, dementia, or significant abnormalities that theinvestigator feels may compromise the patient's safety or successfulparticipation in the study: and

[0107] Inability to understand and sign the Informed Consent toparticipate in this study.

[0108] Prohibited Drugs

[0109] The following medications may not be taken during this study:

[0110] Any antineoplastic agent;

[0111] Any medication known to cause leukopenia:

[0112] Parenteral inotropic agents;

[0113] Nonsteroidal anti-inflammatory drugs, with the exception oflow-dose aspirin (≦325 mg/day); and

[0114] Smoking pattern should not be altered for the duration of theinvestigation as smoking has been found to stimulate the secretion ofAVP from the posterior pituitary gland. Patients must not smokeimmediately prior to blood sampling.

[0115] Allowable Medications

[0116] Digitalis, ACE inhibitors, beta blockers, or other vasodilatorsare allowed but should be at a stable dose for at least 7 days prior tothe Furosemide Balance Phase. The dosage and regimen of any otherchronic, permitted concurrent medications (eg. hormone replacementtherapy, hormone contraceptives, thyroid replacement therapy, or H2antagonists) should be stabilized before the Furosemide Balance Phaseand held constant throughout the study. Any medications prescribedchronically or intermittently during the study or dose adjustments ofthese medications must be reported on the concurrent medication CaseReport Form (CRF). It is recommended that concurrent medications not betaken at the same time as the study drug (eg, within 1-2 hours).

[0117] Efficacy Assessments

[0118] Primary Efficacy Parameter(s)

[0119] The primary efficacy measure is change in urine output frombaseline (obtained on Day 2 of the Baseline Phase [Study Day 6]) to endof treatment (Study Day 9).

[0120] Secondary Efficacy Parameter(s)

[0121] Similarly, secondary efficacy parameters will be evaluated:

[0122] Change from baseline in body weight; and

[0123] Change from baseline in free water clearance. calculated as$C_{H_{2}O} = {V\left( {1 - \frac{Uosm}{Posm}} \right)}$

[0124] where:

[0125] V=Urine volume (mL/day):

[0126] Uosm=Urine osmolality, and

[0127] Posm=Plasma osmolality.

[0128] Change from baseline in effective water clearance, calculated as

V−[2(U_(Na+U) _(K))×V/2(P_(Na+)P_(K))]

[0129] where:

[0130] V=Urine volume;

[0131] U_(Na)=Urine sodium concentration;

[0132] U_(K)=Urine potassium concentration:

[0133] P_(Na)=Plasma sodium concentration; and

[0134] P_(K)=Plasma potassium concentration.

[0135] This formula can be reduced to:$V \times \left( {1 - \frac{U_{Na} + U_{K}}{P_{Na} + P_{K}}} \right)$

[0136] Change from baseline in serum and urine sodium;

[0137] Change from baseline in fractional sodium excretion, calculatedas: ${\text{Fe}_{Na}\%} = {\frac{{CL}_{Na}}{{CL}_{CR}} \times 100}$

[0138] where:

[0139] CL_(Na)=sodium clearance; and

[0140] CL_(CR)=creatinine clearance.

[0141] Number of back-titrations of furosemide

[0142] Laboratory Evaluation

[0143] Full clinical laboratory assessments will be performed atscreening and at the end of Study Days 6 and 9. A clinically significantlaboratory abnormality occurring during the study that has been verifiedby repeat testing will be reported as an adverse event and followeduntil the abnormality has resolved or a satisfactory explanation hasbeen obtained (see Appendix B for a listing of the clinical laboratorydeterminations to be performed).

[0144] Urinalysis

[0145] A urinalysis will be performed at screening and at the end of thestudy (Day 9).

[0146] Other Assessments

[0147] Pharmacokinetic/Pharmacodynamic Analysis

[0148] Plasma concentrations of YM087 and plasma and urineconcentrations of furosemide will be determined throughout the study asoutlined in Appendix A. YM087 concentrations will be measured using avalidated LC/MS/MS method in the positive ionization mode. Furosemideconcentrations will be determined using a validated HPLC method. Forboth assays, sensitivity, specificity, linearity, and reproducibilitywill be determined before analysis of samples.

[0149] A pharmacokinetic/pharmacodynamic analysis will be utilized toevaluate the potential effect of concomitant treatment with YM087 andfurosemide in comparison to furosemide alone. In addition, plasmaconcentrations of furosemide during baseline and treatment phases, willgive information about a potential pharmacokinetic interaction betweenYM087 and furosemide.

[0150] Study Medication

[0151] Description

[0152] Furosemide tablets (40 and 80 mg) and YM087 tablets (10 mg) willbe prepared for the study by the Clinical Pharmaceutical OperationsDepartment. Medication for this protocol will be dispensed according tothe randomization code. All study medications should be stored in asecure, locked area. A detailed set of dispensing instructions will beincluded with the drug shipment.

[0153] Data Analysis and Statistical Considerations

[0154] Power and Sample Size

[0155] This is an exploratory study. Patient numbers are not based onconsiderations of power, but are thought to be adequate to providepreliminary. assessment of the safety and tolerability of YM087 whenadministered concomitantly with furosemide.

[0156] Efficacy Parameters

[0157] The efficacy parameters and changes from baseline will besummarized by treatment group at each collection time. Baseline valuesare defined as those values obtained at the 24 hour time point of StudyDay 6 (end of Baseline Phase). Descriptive statistics will include mean,standard error, median, minimum, maximum, and others as appropriate.

[0158] A urine creatinine will be obtained on all 24-hour urinespecimens in order to determine the accuracy of urine collection.Results will be summarized on those urine samples determined to becomplete 24-hour collections. Additionally, results from all patientswill be summarized.

[0159] Twenty-four patients ranging in age from 41 to 87 with ClassII/Class III CHF (as defined by the New York Heart Association) wererandomized into 1 of 4 treatment groups. Group I received 40 mg offurosemide alone, once a day for 6 days, followed by concomitanttreatment with 20 mg of conivaptan once a day for 3 days. Group IIreceived initial dosing with 40 mg of furosemide. followed byconcomitant dosing with 40 mg of conivaptan. Group III received 80 mg offurosemide initially, then concomitant dosing with 20 mg of conivaptan.Group IV received 80 mg of furosemide alone, and then in continuationwith 40 mg of conivaptan.

[0160] Baseline measurements of urine volume, osmolality, sodium, andpotassium content were obtained on Day 6 (steady state for backgroundfurosemide use), and evaluations of the combination therapy were done onDay 9. The data shown in FIGS. 1 and 2 and in Table 1 below establishthat the aquaretic effects of conivaptan not only persist but areamplified with concurrent use of a loop diuretic. This surprising resultestablishes synergism between the two drugs on urinary water excretion.In addition, the results of urinary sodium excretion shown in FIG. 3 andin Table 1 below establish that combination therapy lessens the loss ofsodium in the urine, particularly as the dose of furosemide isincreased. This surprising result renders the claimed combinationparticularly useful in treatment or prevention of hyponatremia inedematous states like CHF in which therapy with a diuretic is standardcare. Finally, the results on urinary potassium excretion shown in FIG.4 establishes that the combination substantially reduces potassium loss,particularly as the dose of furosemide is increased. This surprisingresult indicates the claimed combination is especially useful intreatment or prevention of hypokalemia in edematous states like CHF inwhich therapy with a diuretic is standard care. In total, the dataestablish that conivaptan in combination with a loop diuretic such asfurosemide can provide increased therapeutic excretion of water inedematous conditions like CHF. Furthermore, the data establish that thedeleterious effects of a loop diuretic on electrolyte loss, particularlypotassium, can be diminished to a surprising extent by concomitanttreatment with a vasopressin antagonist such as conivaptan. TABLE 1Change From Baseline in Pharmacodynamic Parameters (0-6 Hours Postdose)Urine Total Urine Total Urine Urine Osmolality Sodium Potassium Volume(mOsm/kg) (mEq) (mEq) (mL) Mean % Mean % Mean % Mean % Treatment GroupChange Change Change Change F 40 mg/C 20 mg −25.0 −13.8 −1.3 54.4 F 40mg/C 40 mg −13.4 27.6 14.0 79.9 F 80 mg/C 20 mg −43.2 −9.2 −23.1 13.7 F80 mg/C 40 mg −45.5 −32.3 −45.0 −7.8

[0161] The compositions to be employed in the present invention can beprepared and administered in a wide variety of oral and parenteraldosage forms for treating and preventing edematous conditions such asCHF, and promoting electrolyte balance. The compounds can beadministered by injection, that is, intravenously, intramuscularly,intracutaneously. subcutaneously, submucosally, intraductally,intraduodenally, or intraperitoneally. Also, the compounds can beadministered by inhalation, for example, intranasally. Additionally, thecompositions can be administered transdermally. It will be obvious tothose skilled in the art that the following dosage forms may comprise asthe active component, either a compound as a free base, acid, or acorresponding pharmaceutically acceptable salt of such compound. Theactive compound generally is present in a concentration of about 5% toabout 95% by weight of the formulation.

[0162] For preparing pharmaceutical compositions from the compounds ofthe present invention, pharmaceutically acceptable carriers can beeither solid or liquid. Solid form preparations include powders,tablets, pills, capsules, cachets, suppositories, and dispersiblegranules. A solid carrier can be one or more substances which may alsoact as diluents, flavoring agents, solubilizers, lubricants, suspendingagents, binders, preservatives, tablet disintegrating agents, or anencapsulating material.

[0163] In powders, the carrier is a finely divided solid which is in amixture with the finely divided active component.

[0164] In tablets, the active component is mixed with the carrier havingthe necessary binding properties in suitable proportions and compactedin the shape and size desired.

[0165] The powders and tablets preferably contain from 5% or 10% toabout 70% of the active compound. Suitable carriers are magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,starch, gelatin, tragacanth, methylcellulose, sodiumcarboxymethylcellulose, a low melting wax, cocoa butter, and the like.The term “preparation” is intended to include the formulation of theactive compound with encapsulating material as a carrier providing acapsule in which the active component, with or without other carriers,is surrounded by a carrier, which is thus in association with it,Similarly, cachets and lozenges are included. Tablets, powders,capsules, pills, cachets, and lozenges can be used as solid dosage formssuitable for oral administration.

[0166] For preparing suppositories, a low melting wax, such as a mixtureof fatty acid glycerides or cocoa butter, is first melted and the activecomponent is dispersed homogeneously therein as by stirring. The moltenhomogenous mixture is then poured into convenient sized molds, allowedto cool, and thereby to solidify.

[0167] Liquid form preparations include solutions, suspensions, andemulsions, for example, water or water propylene glycol solutions. Forparenteral injection, liquid preparations can be formulated in solutionin aqueous polyethylene glycol solution.

[0168] Aqueous solutions suitable for oral use can be prepared bydissolving the active component in water and adding suitable colorants,flavors, stabilizing, and thickening agents as desired.

[0169] Aqueous suspensions suitable for oral use can be made bydispersing the finely divided active component in water with viscousmaterial, such as natural or synthetic gums, resins, methylcellulose,sodium carboxymethylcellulose, and other well-known suspending agents.

[0170] Also included are solid form preparations which are intended tobe converted, shortly before use, to liquid form preparations for oraladministration. Such liquid forms include solutions, suspensions, andemulsions. These preparations may contain, in addition to the activecomponent, colorants, flavors, stabilizers, buffers, artificial andnatural sweeteners, dispersants, thickeners, solubilizing agents, andthe like.

[0171] The pharmaceutical preparation is preferably in unit dosage form.In such form, the preparation is subdivided into unit doses containingappropriate quantities of the active component. The unit dosage form canbe a packaged preparation, the package containing discrete quantities ofpreparation, such as packeted tablets, capsules, and powders in vials orampoules. Also, the unit dosage form can be a capsule, tablet, cachet,or lozenge itself, or it can be the appropriate number of any of thesein packaged form.

[0172] The quantity of each active component in a unit-dose preparationmay be varied or adjusted from 1 to 1000 mg, preferably 10 to 100 mgaccording to the particular application and the potency of the activecomponent. The composition can, if desired, also contain othercompatible therapeutic agents.

[0173] The following examples illustrate typical formulations that canbe utilized in the invention. Tablet Formulation Ingredient Amount (mg)Conivaptan 25 Furosemide 40 Lactose 30 Cornstarch (for mix) 10Cornstarch (paste) 10 Magnesium stearate (1%) 5 Total 120

[0174] The conivaptan, furosemide, lactose, and cornstarch (for mix) areblended to uniformity. The cornstarch (for paste) is suspended in 200 mLof water and heated with stirring to form a paste. The paste is used togranulate the mixed powders. The wet granules are passed through a No. 8hand screen and dried at 80° C. The dry granules are lubricated with the1% magnesium stearate and pressed into a tablet. Such tablets can beadministered to a human from one to four times a day for treatment ofCHF and other edematous conditions. Preparation for Oral SolutionIngredient Amount Conivaptan 40 mg Furosemide 80 mg Sorbitol solution(70% N.F.) 40 mL Sodium benzoate 20 mg Saccharin  5 mg Red dye 10 mgCherry flavor 20 mg Distilled water q.s. 100 mL 

[0175] The sorbitol solution is added to 40 mL of distilled water, andthe conivaptan and furosemide are dissolved therein. The saccharin,sodium benzoate, flavor, and dye are added and dissolved. The volume isadjusted to 100 mL with distilled water. Each milliliter of syrupcontains 4 mg of invention composition. The composition is administeredto animals to treat edematous states such as heart failure, hepaticfailure, and venous insufficiency.

[0176] Parenteral Solution

[0177] In a solution of 700 mL of propylene glycol and 200 mL of waterfor injection is suspended 20 g of conivaptan and 15 g of furosemide.After suspension is complete, the pH is adjusted to 6.5 with 1 N sodiumhydroxide, and the volume is made up to 1000 mL with water forinjection. The formulation is sterilized, filled into 5.0 mL ampouleseach containing 2.0 mL, and sealed under nitrogen. The composition isadministered to a patient in order to decrease the excretion of sodiumand potassium in the urine, thereby preventing electrolyte imbalanceassociated with CHF and use of a diuretic agent alone.

What is claimed is:
 1. A pharmaceutical composition comprising aneffective amount of a diuretic agent and an effective amount of avasopressin antagonist.
 2. A composition according to claim 1 employinga loop diuretic agent.
 3. A composition according to claim 1 employing avasopressin antagonist of Formula I

wherein R and R⁵ are hydrogen or lower alkyl; R¹, R², and R³independently are hydrogen, halo, lower alkyl, lower alkoxy, amino,alkylamino, or dialkylamino; and R⁴ is hydrogen, phenyl or substitutedphenyl, and pharmaceutically acceptable salts thereof.
 4. A compositionaccording to claim 3 in which the vasopressin antagonist is conivaptan.5. A composition to claim 2 employing furosemide.
 6. A composition toclaim 5 employing the vasopressin antagonist conivaptan.
 7. A method forpreventing and treating congestive heart failure and other edematousconditions in a mammal comprising administering an effective amount of acombination of at least one diuretic agent and at least one vasopressinantagonist.
 8. A method according to claim 7 wherein furosemide isadministered in combination with conivaptan.
 9. A method for inhibitingexcretion of sodium ions in the urine of an animal comprisingadministering to the animal an effective amount of a diuretic incombination with a vasopressin antagonist.
 10. A method according toclaim 9 wherein the diuretic administered is a loop diuretic.
 11. Amethod according to claim 10 wherein furosemide is administered incombination with conivaptan.
 12. A method for inhibiting the excretionof potassium ions in the urine of an animal comprising administering tothe animal an effective amount of a diuretic in combination with avasopressin antagonist.
 13. A method according to claim 12 wherein thediuretic is a loop diuretic.
 14. A method according to claim 13 whereinfurosemide is administered in combination with conivaptan.
 15. A methodfor treating edematous states in an animal comprising administering aneffective amount of a diuretic agent in combination with a vasopressinantagonist.